Varroa mites are external honeybee parasites that attack honeybees and can wipe out a colony. The mites suck the blood from both the adults and the developing brood, weakening and shortening the life span of the ones on which they feed. Emerging brood may be deformed with missing legs or wings. Untreated infestations of varroa mites that are allowed to increase will kill honeybee colonies.
Various treatments and pesticides are known for treatment of mites. Fluvalinate, a synthetic pyrenthoroid, available under the designation Apistan™, is a common pesticide for varroa mites. Apistan is available impregnated into plastic strips, which are hung between frames in the hive. CheckMite+™ is another pesticide-impregnated plastic strip that is commonly used. Recommended treatment of mites is to hang two strips (either Apistan, CheckMite+, or other) in the brood nest area of the colony for the allotted time, which is approximately 4 weeks for Apistan and approximately 42-45 days for CheckMite+. After the suggested treatment period, the recommended action is to remove the strips from the hive, as the amount of active ingredient remaining in the strips is typically too low to affect the mites. However, many beekeepers leave the strips in after their useful life.
Leaving the strips in past their useful life can be detrimental to the fight against the mites. Having a low-dose strip in the hive provides a false sense of security to the beekeeper that the hive is being treated. Additionally, extended exposure to low levels of pesticide may build the mites' resistance to the pesticide.
Improvements in pesticide strips, and their use, are desired.